The PS3 has been one misstep after another for SONY. Making it intentionally harder to program for, giving it (fixed allocation) RAM amounts that would make an office computer burst out laughing, pricing it the highest of any console at the time, releasing it with low amount of launch titles, and then of course the whole PSN security fiasco.
I gotta hand it to em. Despite all the failings of it, they still managed to make people buy it, though there's no arguing that the other two major consoles, Wii and Xbox360, "won" this generation.
That Bethesda released Skyrim for it was, of course, a no brainer at the time, but I'm sure it has meant no end of headaches for them despite the money it brought in.
Honestly, I can't blame them from having the same problems now with the DLC; they probably worked very hard to finally squeeze the massive Skyrim into the few system resources the console had. And now with Dawnguard and Hearthfire they face the same problems again. More stuff that wants to use the already cramped memory. Hearthfire especially, since graphical customization in-game always eats up lots of it.
That's not to say that Bethesda don't sort of "owe" the PS3 users the content. Since they released the original for it, it's only fair that the expansions arrive there as well. The transparancy they're showing with all this is also commendable. It's better, and more honest, to admit now that they have problems then to release a buggy mess and hope to fix it later.. yknow, like everyone else is doing with porting jobs these days :/